1. Field of the Invention
This invention relates to a deflector to be used to control the electron beam typically for writing a pattern of semiconductor devices and also to an equipment of electron beam lithography including such a deflector.
2. Description of the Related Art
An elevated accuracy level is required for mask processing in response to shrinking of semiconductor devices in recent years. An equipment of electron beam lithography is currently available to be possible highly accurately masks processing. Such equipment of electron beam lithography are adapted to control an electron beam so as to make it accurately strike a desired spot. An electrostatic deflector is typically used for controlling an electron beam.
In the electrostatic deflector, a plurality of individually insulated trapezoidal bulk electrodes are arranged symmetrically relative to the center axis of the irradiated electron beam and the electron beam is controlled for its position and other factors by subjecting each of the electrodes to predetermined potential changes.
When a deflection potential is applied to a predetermined electrode, a micro potential is generated in the adjacent electrodes to which no deflection potential is applied to give rise to a problem of a cross talk. Jpn. Pat. Appln. Laid-Open Publication No. 2002-198294 and other patent documents propose techniques of arranging an earth electrode between adjacent electrodes. However, the cross talk appears not only between electrodes but also in other areas and it is not satisfactory to control potential between adjacent electrodes.
On the other hand, a signal wire for supplying a deflection potential and an earth wire are connected to each electrode. Normally, the earth wire is drawing to the outer peripheral side of the electrode and the route of the earth wire is not particularly fixed. However, since the impedance of the electrode varies as a function of the route of the earth wire, the deflection potential can fluctuate to degrade the accuracy of controlling the electron beam.